Deleting Records V6.1/Progress DB

Greetings! Does anyone know how to delete a record from Vantage. I used the
part import tool to upload invoices and some of the invoices were uploaded
with no Invoice number, I should have proofed better (Vantage should not
allow a null value here either). Well anyway I cant select it and when I
try to created another invoice it assigns a null value to it too. My last
record uploaded was blank!

Any help is appreciated!
Brian